Lubricant composition



Patented Jam 16, 1951 LUBRICANT COMPOSITION Robert L. May, Chicago, Ill., assignor to Sinclair Refining Company, New York, N. Y., a corporation of Maine N Drawing.

Application August 23, 1946,

Serial N 0. 692,7

oil composition particularly useful as a heavy duty oil lubricant for internal combustion engines and having improved characteristics especially with respect to oxidation and corrosion and cleanliness of engine operation.

In my co-pending application Serial No. 545,193 filed July 15, 1944, of which the present application is in part a continuation, and which issued October 22, 1946, as Patent No. 2,409,877, there is described and claimed a mineral oil composition consisting essentially of a petroleum lubricating oil fraction and a minor proportion of an oxidation and corrosion inhibiting addition agent resulting from the reaction of an alkylated phenol with the condensation product of turpentine and phosphorus pentasulfide, the addition agent being more fully described and claimed in my Patent 2,379,312; For convenience, these addition agents are herein referred to as the oxidationand corrosion inhibitor or merely as the inhibitor.

,In the above noted co-pending application I have also disclosed that the use of these inhibitorsalone in proportions as great as about 1% of a 50% concentrate of the inhibitor or higher is subject to the disadvantage that there is a tendency toward sludging, due to excess phosphorus acidity, and that where such proportions of the inhibitor are used the efiectiveness of the oil composition as an internal combustion engine lubricant is materially improved by the inclusion in the oil composition of a minor proportion of a so-called detergent consisting of an organic salt, or soap, of a metal capable of neutralizing the phosphorus acidity of the above noted oxidation and corrosion inhibitor. Y

The present invention is directed particularly to my improved mineral oil compositioncontaining-such detergent in conjunction with the oxidation and corrosion inhibitor of my said co-pendingapplication, and provides means whereby the inhibitor may be used in proportions in excess of 0.5% by weight without experiencing difliculty due to excess phosphorus acidity.

Various organic salts and soaps have been found materially to improve the cleanliness of operation of internal combustion engines, when added in relatively small proportions to the lubricating oil usedin such engines, and have been used for this purpose and commonly designated detergents; Notably among such detergents are the calcium, sodium and barium petroleum sulfonates, various calcium salicylates, especially calolum cctyl 'salicylates. barium phenolate of sul- 3 Claims. (Cl. 252-46-6) furized diamyl phenol, calcium and barium phenolates of sulphurized tertiary amyl phenol, respectively, calcium soaps of oxidized lubricating oil acids such as that currently marketed in admixture with oil and containing about 1.75% calcium, and calcium ortho-lauroyl cresolate, described in Patent 2,307,615 to Barth.

These detergents have been found to be effective in inhibiting oxidation of the mineral oil with which they are admixed, over a substantial period of time, commonly designated the oxidation induction period. However, at the end of the oxidation induction period, these detergents appear to exert a prooxidant elfect on the oil.

I havediscovered that by the use of a detergent of the class noted in conjunction with the oxidation and corrosion inhibitor of my Patent No. 2,409,877 the disadvantageous tendencies of each of these materials when used alone are materially minimized. When so used together these materials have been found to be compatible, each accomplishing its intended purpose without destroying the effectiveness of the other. But, in addition, these two classes of additives have been found to complement each other in such a way that excess phosphorus acidity of the inhibitor is effectively neutralized by the detergent, thus minimizing any tendency of the former to promote sludge formation, especially when the inhibitor is present in proportion as great as 0.5% or greater. Further the tendency of the detergent to promote oxidation of the oil at the termination of the oxidation induction period is also minimized by the presence of the inhibitor.

The proportions of the inhibitor and of the detergent used in the compounding of my improved mineral oil composition may be varied somewhat but in each case only a minor proportion of each is used. The proportion of the inhibitor is advantageous in excess of 0.5% by weight and may be as high as about 2.5% depending upon the amount and basicity of the detergent used. The detergent should be used in an amount at least sufficient to neutralize excess 7 phosphorus acidity. The optimum proportion to be used will vary somewhat with the particular inhibitor and detergent used and the intended use of the oil composition.

The oxidation and induction inhibitor is usually prepared as a concentrate in a petroleum lubricating oil fraction, as hereinafter more fully described. The optimum ratio of the amount of detergent to the amount of inhibitor used will depend to a considerable extent on the basicity of the detergent and upon the amount of Pass equivalent used in the preparation of the inhibitor and may be determined to any particular set of conditions by simple test. Usually the proportion of the inhibitor should not exceed that which will be neutralized by the detergent, as previously noted.

Various petroleum lubricating oil fractions may be used as the mineral oil constituent, for instance, Acid Treated Coastal Oil SAE- 40, Acid. Treated Mid-Continent Oil SAE 10, Solvent Treated Mid-Continent Oil SAE or blendsrof such oils with bright stock or a solvent refined lubricating oil fraction from a Pennsylvania crude.

The invention will be hereinafter illustrated by specific examples of my improved .mineral ,oil;.

compositions. Since the characteristics of .the inhibitor are somewhat affected by the .charac.. teristics of the turpentine-P285 condensation product used in its preparation and the nature and proportion of the alkylated phenol reacted therewith, the illustrations of my lubricating oil composition will include a description ofthe preparation of the particular inhibitor used.

In the preparationof the intermediate turpentine-PZSE, condensation product to be used in preparing my inhibitor, the molarratio of turpentine to PzSs usedis with'advantage approximately- 311 though this ratio may be varied somewhat as subsequently described.

The reaction of turpentine with PzSs is highly exothermic and proceeds-spontaneously after being initiated by slight heating. A- desirable method of efiecting the reaction is to heat the turpentine in a vessel to about 200 F. or slightly higher and them-without further heating, slowly stirring in the phosphorus pentasulfidein the powdered form. The heat of reaction is great and, consequently, the addition should be made slowly, so as to avoidthe possibility of the reactions becoming uncontrollable. The characteristics of the inhibitor are favorably afiected: byusing in its preparation a turpentine-P285 cone densation product inthepreparation of which the temperature during the mixing-was not per mitted to exceed about 250 although higher temperatures are permissible;

After the additionis completedgit issusua'lly necessary to: apply heat externally tocomplete the reaction. The temperature during this last. stage is preferablymaintained at about 300 'F;, though temperatures of about. 2-00*F;:ton 400 F." may be employed. This second stage of. the op-. eration should be continued until all. of. the P285: is. dissolved. The materialthus prepared is .a viscous liquid at elevated temperatures; which solidifies on coolingto room temperature.

The: turpentine-P285 concentration products,"- thus prepared, are, in theabsence of excess tur pentine, brittle, resinous solids which dissolvereadily in lubricating oils or in excess turpentine: to form liquids. Such solutions-of high concentration are relatively viscous. However, thev viscosity of the solution decreases rapidly as the proportion of the solvent is increased from 25% to 75%.

Ingeneral, my inhibitor may be prepared by' adding the alkylated phenolgradually' to the turpentine-P285 condensation product prepared as previously described.- Such addition is a'dVantageous at a temperature of about-230 F. However, this temperature may be varied, temperatures as high as 300 F. being used without damage to the product.

In reactingthe alkylated' phenol with the -tur-= pentine-Pzss condensation product, very little heat is evolved. After the alkylated phenol has been added, the mixture is maintained at an elevated temperature, advantageously about 200 F. for about an hour with stirring. Satis factory results have also been obtained where the alkyl-ated phenol is added :to the g conjdensation product at a temperatureof2'75-28O" Ffand the mixture maintained at that temperature for about ten hours.

The proportions of the alkylated phenol may be varied over a considerable range Without loss of -'the eiiectiveness-of the resulting inhibitor. The optimumproportion of alkylated phenol used is, to a considerable extent, dependent upon the :ratio of turpentine to P285 used in the preparation. of the intermediate condensation product, Particularly desirable results have been obtained using proportions of reactants equivalent to about 2 mols of PzSs, 6 mols of turpentine andB mols of alliylated'phenol, assuming-the molecular Weight of turpentine to 'b'e-13'6. Howevntlie' proportions of -thesecons'titu'ents may be varied somewhat. Satisfactory results may be-obtaifid where for each two mols of Piss, 5 to 8 'mols'f of turpentine and l to 5"Inols*of thealkyl'ate'd phenols areused. However, I have iound'it aesirable that the-total munber of 'niols of turpe'r'i tineand alkylated phenol used -for 'ea'ch two mois of P285 fall within a range of about 8 to 10 Also; in'the preparation of the turpentine-P285 c'o'ndensation product used ei ar'mgtn inhibitor; 1 I have found it desirable that ho unfeactd' Pz'Ss' remain in the produt:=-

In the preparation of my new class of inhibi tors, considerable latitude is permissible in the selection of the alkylatd' ph'nolusd. I have used with advantage alkylated" phnols'in which the alkylradical of the alkylated'plin'ol is-a saturated "aliphatic group, nets-51y diarnyl'phenol However; other -alkylated phenols may be; used with advantage for instance, p-cyclohexylphenoly Pentaphen and "tl'1'- --upper boiling petroleum V cresyl-i'c acids. nach moieeme of -the alkyla'ted phenol may contain oneor"-r-'ric' fe' sues great -r The number of carbon atoms ineach aliphaticgroup "is hotcritial? Desirable-premiersmay be-obtained-where eacli such group contains from" I up to 12 to 16} or even upto 25 615 carbon atoms- Alkylated-phnols containing 5 or more carbon atoms iri each alkyl group-nave been foundespecially desirabl" in the "-pre'par' ti' on of my new i'nliibito'rs, because of the grea' i er Oil solubility of tner sultafir;prdaucts; The

alkyl grtup-or gmu s may be either nemaror at'ed phenols are "c'o'mpris'efd primar ny or mo andpoly alkylat'edphenols haying alkyl group asnoted above} but with Cs alkyl g-roups pie dominating;

I' have further used with 'adva ntage'in the p'r'e'p' aratio'n 01fimprovedinhibitors, alkylated' phenols, herein designatedcodim'e'r ibOttUmS QT- kylated ph'e'nols;preparedtbwthlimethod just de *scribedior the preparation of codimer 'alkylated phenols except't-hat the phenol was'reacted with 'codim'er bottoms, the codimer bottoms used being the bottoms obtained by a redistillation of the previouslydescribed codimer to a 350 to 360 F. end point'overhead. This bottoms was comprised primarily of C12 .olefines, but contains some somewhat lower and some somewhat higher molecular weight olefines. v In thepreparation of the turpentine-Pzss condensation 5 product, either steam-distilled wood turpentine or gum spirits may be used. Such turpentine consists mainly of alpha pinene, a bi-cyclic terpene havingthe empirical formula C1nI-I1s.- Pure alpha 'pinene and other more costly 'terpenes will react similarly with P285, but, for 'reasonsincluding economic considerations, I generally prefer to use the more readily available turpentines. The turpentine usedin the specific exampies herein was a product known to the trade as-Pinene 111. t 1 Various, specific examples of these .inhibitors 'andthedetails of their production are included inmy'PatentNo. 2,409,877. Irraddition to those 'the'following may be noted:

Example! I.

1,088 grams (8 mols) of Pinene 111 was placed in a 5 liter, three-necked flask equipped with a stirrer and thermometer and the temperature raised to 250 F. 'Then 444 grams (2 mols) of P25 was added portionwise so as to maintain the temperature of the mixture between 250 to 275 F. this addition requiring 1 to 2 hours. After all of the PzSe'hadbeen added the mixture was heatedfor 7 hours at a temperature of 275 F. Thereafter- 352 grams 2 mols) of p-cyc'lohexylphenol was added and the mixture heated an additional 4 hours at 275 When the, resultant :reaction was finished 2,045 grams of a petroleum lubricating oil fraction was added to reduce the viscosity of the product and reduce the percentage of the phosphorus pentasulfide in the resultant mixture to 11.3%. The mixture was then stirred an additional 30 minutes and was filtered while hot to give 3,929 grams of the final product. This product had an acid number of 12.2, a specific gravity of 0.9847 and contained 3.11% phosphorus and 8.41% sulfur.

Example II The procedure used in the preparation of this material was the same as that used in Example I except that 164 grams (1 mol) of Pentaphen was substituted for one mol of the p-cyclohexylphenol used in Example I and 2,057 grams of the mineral 6 Example IV This material was likewise made by the procedure of Example I except that 200 grams (1 mol) of the cresylic acids used in Example II was substituted for 1 mol of the p-cyclohexylphenol of Example I, and 2,021 grams of the mineral oil was added. The yield was 3,929 grains and the acid number of the product was 2.3; Its specific gravity was 0.9861 and it contained 3.05% phosphorus and 7.7% sulfur.

1, The. effectiveness of my improved mineral oil composition as an internal combustion engine lubricant is illustrated'by the following results 'of 36'hour engine tests using different detergents in conjunction with my inhibitor in various base 'oils. [In the following four tests, the base oil used was an acid treated Coastal Oil SAE 40 to which there was added 0.001% of a conventional foam inhibitor. The oilftemperature in each case was Where neither inhibitor nor detergent was added to the base oil tested, the total varnish and sludge rating was 77, the bearing corrosion loss was 1.344 grams and analysis of the oil after the test showed an acid number oi 1.5 and a viscosity rise of 219% t 100 F, y a v Where two parts of the inhibitor, such as pro- .duced in Example I, and 4 parts of calcium isooctyl salicylate wereadded for each 94 parts or -the base oil, the total varnish and sludge rating was increased to 96.5, a very substantial improve 'ment, the bearing loss was only 0.034 grams and oil was added. The yield was 3,929 grams and j analysis of the oil after the test showed an acid number of 0.5 and a; viscosity rise of only 29.2%.

Where two parts of the same inhibitor and 16 ,parts of a solution of sodium mahogany sulfonate,

consisting of 10 parts of the sulfonat'e and 90 parts of oil, were added for each 82 parts of the base oil, the total varnish and sludge rating was 82.5, the bearing corrosion loss was 0.140 gram and analysis of the oil after test showed an acid number of 1.4 and a viscosity rise of 66%.

Where 2.5 parts of the same inhibitor and 5 parts of a mixture of calcium soaps of oxidized lubricating oil acids in admixture with unoxidized lubricating oil and containing about 1.75% of calcium, previously identified, were added for each 92.5 parts of the base oil, the total varnish and sludge rating was 84.5, the bearing corrosion loss was 0.168 gram and analysis of the oil after the test shows an acid number of 2.8 and a viscosity rise of 113.1%.

In a similar test using as the base oil a solvent treated Mid-Continent SAE oil the test of base oil alone, at an engine temperature of 265 F., showed a total varnish and sludge rating of 91, a bearing corrosion loss of 2.979 grams and analysis of the oil after the test showed an acid number of 2 and a viscosity rise of 484%.

Where 2.2 parts of the same inhibitor used in the preceding examples, 14.7 parts of calcium petroleum sulfonate, consisting of 10 parts of oil free calcium mahogany sulfonate in parts of a lubricating oil fraction, 0.001 part of the foam inhibitor and 0.1 part of a conventional pour depresser were added for each 83 parts of the base oil, the total varnish and sludge rating was 96, the bearing corrosion loss was 0.059 gram and analysis of the oil after the test showed an acid number of 1.6 and a viscosity rise of only 17.7%.

A further oil subjected to this test, at an engine temperature of 265 F., consisted of 69.7 parts of an acid treated Mid-Continent SAE 10 base oil,

formation due to phosphorus acidity.

In each of the foregoing tests. with' the: ex. Caption of tests on the blank oil, the proportiom of the inhibitor used was in excess of that which could be used in the absence of the det erg'ent without evidence of a tendency awarde -age By the inclusion of the detergent, this tendency was minimized as shown by the foregoing tests, in each instance the varnish sludge rating being in excess of that of the base oil in which the inhibitor was not included.

Further tests of base oils containing calcium ortholauroyl cresolate in conjunction with the inhibitors have shown a coke formation of only 0.06 gram where tests of the base oil alone showed 0.68 gram of coke.

A further advantage of my present invention, particularly as applied to solvent refined Mid-- Continent and Pennsylvania Oils, is the clearness of the blend. It has been observed that when even relatively small proportions of the inhibitor, say of the order of 0.5%, are blended with such highly refined oils there is a tendency toward a slight haziness of the mixture. However, where a small amount of one of the herein described detergents is also present, up to 2.5 to 3 of the inhibitor may be added Without causing noticeable haziness of the blend.

The method employed in determining the total varnish and sludge ratings, noted herein; is that described in the U. S.- Army Tentative Specification AXS-l554.

I claim:

1. A mineral oil composition consisting essentially of a major portion of a petroleum lubrieating oil fraction, a minor proportion cfiective to retard oxidation of the oil but not less than about 0.5%, of an inhibitor resulting from the reaction of an alkylated phenol with the condensation product of turpentine and phosphorus pentasulfide and a minor proportion efiectiv toat least neutralize excess phosphorus acidity,

of a detergent of the class consisting of calcium and barium petroleum sulfbn-ates;

' 2.-A fiiineraloil composition consisting essentially or a Thai or proportion of a petroleum lubrieating oiliraction, a minor proportion-, efieetive to retardoxidation of the oil but not less'than about-0L5 of an inhibitor resulting from the reactionof an alkyl-ated phenol with the condensation product of turpentine andphosphorus pentasulfide and in which. excess phosphorus acidity is at least neutral-i'zedbythe addition of barium petroleum sulfonate;

'3. A mineral oil composition consisting essentially of a major proportion of a petroleum lubri eatingon fraction,- a minor vproportion, effective to retard oxidation of theoil' but not less than about 0.5%; of an inhibitor resulting from the reaction of an alkylated phenol with the con densation product of turpentine and phosphorus pentasulfide and in which excess phosphorus acidity is at least neutralized by the addition of calcium petroleum sulfonatz I RQBERT L. MAY. REFERENCES 'oIrED The following references are of retard in the file of this patent: f v

UNITED STATES 1 

1. A MINERAL OIL COMPOSITION CONSISTING ESSENTIALLY OF A MAJOR PORTION OF A PETROLEUM LUBRICATING OIL FRACTION, A MINOR PROPORTION, EFFECTIVE TO RETARD OXIDATION OF THE OIL BUT NOT LESS THAN ABOUT 0.5%, OF AN INHIBITOR RESULTING FROM THE REACTION OF AN ALKYLATED PHENOL WITH THE CONDENSATION PRODUCT OF TURPENTINE AND PHOSPHORUS PENTASULFIDE AND A MINOR PROPORTION EFFECTIVE TO AT LEAST NEUTRALIZE EXCESS PHOSPHORUS ACIDITY, OF A DETERGENT OF THE CLASS CONSISTING OF CALCIUM AND BARIUM PETROLEUM SULFONATES. 